The present invention relates generally to automated distribution systems for storing and retrieving goods in a warehouse. More particularly, the invention relates to a high volume conveyor accumulator and container driver assemblies for delivering articles/containers to and retrieving articles/containers from a storage carousel.
In conventional high volume storage, containers are stored on pallets. The pallets are stored on shelves of a storage rack until such a time that a container on the pallet is needed. To store a container or containers, a pallet is retrieved from the storage rack by a stacker truck or crane or forklift. The container or containers is then placed on the pallet, which is then returned to the storage rack by the stacker truck. Retrieval of a container requires unloading of the pallet, which holds the container, from the rack by the stacker truck and removing the container from the pallet. Then the container is delivered to a desired location, either by the stacker truck or on a conveyor, where it can be loaded onto a delivery truck or other means of transportation. Unless the pallet is cleared of all containers, the pallet is then replaced back in the storage rack.
The draw backs to the conventional rack and pallet system are numerous. Although somewhat automated through the use of stacker trucks and forklifts, the process is slow and arduous. A stationary rack and pallet system tends to be the bottle neck of any warehouse. An efficient storage and retrieval system should have the ability to store and retrieve a wide variety of goods housed in a wide variety of containers and to rapidly and effectively dispense the retrieved items and provide reasonable access to the stored containers.
Other proposed warehousing and distribution systems have incorporated a moving carousel. The carousel is indexed so that a shelf supporting the desired container can be moved to a retrieval location where the container can be retrieved from the shelf or so that an empty shelf can be moved to a delivery location where a container can be delivered to and placed on the empty shelf for storage on the carousel. However, since carousels tend to be large, weighing up to a couple hundred tons, stopping and starting the carousel requires a great amount of energy and exerts a significant strain on the system and the individual parts of the carousel. To overcome these problems, some carousels have been designed to continuously move. Retrieval and delivery of the containers from the continuously moving carousel is accomplished by means of equipment which deposits the containers onto the shelves of the moving carousel or grabs the containers from the shelves of the moving carousel without disturbing the carousel or the adjacent containers. Typically, these continuously moving carousels employ "totes", which are smaller than pallets but still require the container to be removed from the tote and the tote replaced back on the carousel. Furthermore, the "totes" limit the size of the containers that can be stored on the carousel.
For example, in U.S. Pat. No. 5,505,586 to Lichti, a high speed storage system is disclosed, which includes a storage carousel and a vertical conveyor. The shelves of the conveyor and the vertical lift include irregular side edges to accommodate the forks of the shuttle unit, which transfers the articles to and from the lift and carousel. These irregular side edges restrict the size of the containers supported thereon and, therefore, limit the scope of application.
In U.S. Pat. No. 4,983,091 to Lichti, Sr. et al., a "toteless" storage carousel and delivering and retrieving mechanisms for inserting and extracting containers from the carousel while it is continuously moving are disclosed. Containers are transferred to the carousel by a shuttle which includes gripping arms. The gripping arms as disclosed, however, limit the size of the packages on the carousel.